Which of the following statements best describes the long-run aggregate supply curve?
a. It is vertical because wages and input prices are fixed in the long run.
b. It is vertical because wages and input prices are fully flexible in the long run.
c. It is vertical because potential output is determined by a country’s central bank.
d. It is upward sloping because wages and input prices are fixed in the long run.
e. It is upward sloping because savings increase as interest rates rise.